Hydraulic and electrical power unit



June 2, 1970 E. J. SVENSON 3,515,167

HYDRAULIC AND ELECTRICAL POWER UNIT Filed Aug. 22, 1968 3 Sheets-Sheet 1{43.1 5 v A 10\ $0 4 1L;

June 2, 19% E. J. SVENSON HYDRAULIC AND ELECTRICAL POWER UNIT 3Sheets-Sheet 2;

Filed Aug. 22, 1968 ziwrza z wwwm June 2, 1970 E J. SVENSON 3,515,167

HYDRAULIC AND ELECTRICAL POWER UNIT I Filed Aug. 22, 1968 5 Sheets-Sheet5 65 Jive/d5? I flrzesz f uerw'arz/ 1w, wwwadmm United States Patent3,515,167 HYDRAULIC AND ELECTRICAL POWER UNIT Ernest J. Svenson, 233023rd Ave., Rockford, II]. 61105 Filed Aug. 22, 1968, Ser. No. 754,687Int. Cl. E03b 11/16; F1511 15/18 U.S. Cl. 137565 10 Claims ABSTRACT OFTHE DISCLOSURE There is disclosed an electrically driven hydraulic pumpunit having a motor end bell which serves as a valve and fluid passagehousing in which an outlet check valve and a release valve are coaxiallyarranged. An oil reservoir is connected with the valve and isconstructed for minimizing aeration or foaming of oil returned to thereservoir.

The present invention relates to a novel power unit, and morespecifically to a novel electrically driven hydraulic power unit orpump.

It is an important object of the present invention to provide a novelpower or pump unit comprising an electric motor, a hydraulic pump and anoil reservoir, which unit is constructed so that it is efficient inoperation and so that it may be easily and economically manufactured andserviced.

A more specific object of the present invention is to provide a novelunit of the above described type wherein the electric motor and thehydraulic pump comprise a common member in which fluid passageway andvalve means are formed and assembled in a manner which facilitatesmanufacture and servicing.

A further object of the present invention is to provide a novel unit ofthe above-described type having one or more oil return lines extendingfrom the pump into the reservoir, which lines and reservoir areconstructed for minimizing aeration or foaming of the returning oilwhereby to promote more eificient operation of the unit.

A still more specific object of the present invention is to provide anovel unit comprising an electric motor having an end member or bellthrough which its drive shaft extends, a hydraulic pump assembled withand including as a part thereof said end member or bell and driven bysaid drive shaft, which end member has formed and assembled thereinfluid passageways and outlet check and release valve means coaxiallyarranged, and a hydraulic fluid reservoir removably connected to saidend member or bell and into which oil return lines extend, saidreservoir including baffle means associated with said return lines forminimizing foaming of oil returned to the reservoir.

Other objects and advantages of the present invention will becomeapparent from the following description and the accompanying drawingswherein:

FIG. 1 is a plan view partially in section showing a unit incorporatingfeatures of the present invention taken generally along the line 11 ofFIG. 2;

FIG. 2 is a front elevational view partially in section taken generallyalong the line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line 33 in FIG. 2;

FIG. 4 is an enlarged fragmentary partial sectional view showing aportion of the valve structure in greater detail;

FIG. 5 is a fragmentary sectional view taken along line 55 in FIG. 1;and

FIG. 6 is a schematic view showing the hydraulic circuit of the powerunit.

Referring now more specifically to the drawings wherein like parts aredesignated by the same numerals through.

out the various figures, a hydraulic and electrical power unit 10incorporating features of the present invention is Shown in FIGS. 1 and2. The unit comprises an electric motor 12 having an end member or hell14 in which a bearing unit 16 is mounted for supporting a motor driveshaft 18. The remainder of the motor may be of known construction andneed not be described in detail.

The unit 10 further comprises a hydraulic pump 20 which also includes asa part thereof the end member or bell 14. An oil reservoir 22 describedin greater detail below has an end margin telescoped around a reduceddiameter portion 24 of the member 14 nad sealed with respect thereto byan O-ring 26 or other suitable means. The reservoir is detachablysecured to the member 14 by a plurality of screws 28 shown in FIG. 5.

The pump means 20 of the unit has a housing 30 detachably securedagainst a face 32 of the member 14 by a plurality of screws 34 or othersuitable fastening means. A pumping chamber 36, FIG. 1, is formed in thehousing 30 for receiving complementary meshing gears 38 and 40, FIG. 2,respectively mounted on shafts 42 and 44 to provide a gear pump. Asshown in FIG. 2, first ends of the shafts 42 and 44 are supportedrespectively by bearings 46 and 48 mounted in the housing 30 andopposite ends of the shafts are supported respectively by bearings 50and 52 mounted in the member 14. In addition, the shaft 42 is extendedand is detachably connected to the motor shaft 18 by a coupling element54. It will be noted that the coupling element 54 and the end of theshaft 18 are formed so that they may be selectively interlockinglyengaged or disengaged during assembly or disassembly of the unit bybeing axially shifted toward or away from each other. In the embodimentshown, the end of the shaft 18 is formed with a slot for accommodating acomplementary lug or projection of the coupling element 54. A suitableseal 56 is mounted in the member 14 and encircles the shaft 42 forpreventing the leakage of oil along said shaft. The upper level of oilin the reservoir 22 is indicated by a dot-dash line 57, and oil isdesignated by a similar numeral.

As shown in FIGS. 1 and 6, the pump housing 30 is formed with an inletpassageway 58 communicating with the pump chamber 36. An inlet conduitor pipe 60 is connected with the housing member 30 and the inletpassageway or port 58, which pipe carries an oil filter 62. An outletport 64 is formed in the housing 30 and communicates with a passageway66 in the member 14. As shown in FIGS. 1, 3 and 6, the passageway 66intersects cross passageways 68 and 70 formed in the member 14. Thepasageway 68 has a valve seat element 72 (FIG. 3) positioned thereinagainst which a pressure relief valve element or ball 74 is pressed by aspring 76.

The passageway 68 communicates through the valve seat with a valvechamber 78 which in turn communicates with an oil return passageway 80,FIGS. 1 and 6, formed in the member 14 and to which a return conduit 82to be described more in detail below is connected. The compression ofthe spring 76 may be adjusted in accordance with the pressure at whichthe valve 74 is to open. In the embodiment shown, this adjustment, FIGS.3 and 6, is accomplished by a hollow threaded member 84 enclosing andengaging an outer end of the spring 76. The member 84 is accommodated byan internally threaded portion 86 of the valve chamber 78. The outer endof the element 84, FIG. 3, is enclosed within a threaded cap 88 which isadapted to compress a sealing ring 89 and thus secure the member 84 in asealed position of adjustment.

The high pressure fluid passageway 70 intersects another passageway orbore 90 which completely traverses the member 14 as shown in FIG. 3. Anouter end of the passageway 70 is closed by a plug 92. The bore 90communicates with an outlet port 94 through valve means designatedgenerally by the numeral 91 which outlet port in turn is adapted to beconnected by a suitable hydraulic conduit 96 with a device to beactuated. In the embodiment shown schematically in FIG. 6, the hydraulicconduit or line 96 is connected with an actuator cylinder 98 having acomplementary piston 100 and piston rod 101 adapted to elevate a workmember 102.

The pasageway 90 is intersected by another cross passageway 104, theouter end of which is closed by a plug 106. The passageway 104communicates with an outlet port 108 which in turn is connected with anoil return conduit or pipe 110 extending into the reservoir as shown inFIGS. 1 and and described below.

In accordance with a feature of the present invention, the valve meansor mechanism 91 is disposed within the passageway 90 for controlling theflow of hydraulic fluid to and from the actuator cylinder 98. This valvemechanism 91 is efficient in operation and is adapted to be easilyassembled and serviced. As shown in FIG. 3, the valve means 91 issupported at one extremity by an element 112 having an outer end or plugportion 114 threaded into and sealing one end of the passageway 90. Theelement 112 has a reduced diameter inner end portion 116 formed with atransverse passageway 118 communicating with the passageway 70. Anaxially extending bore 120 in an inner end of the portion 116communicates with the transverse passageway 118 and the inner endthereof is defined by a valve seat 122. An O-ring 124 serves to preventleakage between the reduced diameter or stem portion 116 and the walldefining the passageway 90. A check valve element 126, which in theembodiment shown is in the form of a ball, engages the valve seat 122for preventing reverse flow of fluid.

An opposite end of the passageway 90 is closed by an element 128 havingan outer end or plug portion 130 threaded into the body member 14. Theelement 128 also has a transverse passageway 132 communicating with thepassageway 104 in the body member 14 and an axially extending passageway134 having its inner end defined by a valve seat 136. A check valveelement or ball 138 engages the seat 136 and an O-ring 140 is employedfor preventing fluid leakage between an inner end portion 142 of theelement 128 and the wall defining the passageway 90.

The valve elements 126 and 138 of the valve mechanism 91 arerespectively normally maintained in engagement with their seats 122 and136 by a compression spring 144 as shown in FIGS. 3 and 4. Preferably,opposite end coils 146 and 148 of the spring are snapped into grooves150 and 152 formed in the valve elements 126 and 138 respectively sothat the valve elements and the spring may be handled and assembled as aunit. A slotted tubular gauge or guide 154 extends between and encirclesthe valve elements 126 and 138 for the purpose of maintaining them inproper operative position.

The valve element 138 is adapted to be unseated by mechanical means soas to permit lowering of the piston 100 and the load of the work member102. More specifically, a valve actuating plunger 156, FIG. 3, isslidably mounted in the element 128 and is provided with an inner endportion 158 of reduced diameter extending within the axial passageway134 for engagement with the ball element 138. An adjustment screw 159has a threaded coupling with an outer end of the plunger 156 and isdisposed for engagement by a cam 160 pivotally mounted on a pin 162 andadapted to be actuated by a handle or lever 164. As shown best in FIG.3, the cam is shaped so that when the lever is in the position shown,the plunger 156 is retractable sufficiently to enable the ball 138 toengage the seat 136 and thereby the return of the hydraulic fluid to thereservoir. When the lever is pivoted in a clockwise direction to thedotted position as viewed in FIG. 3, a high portion of the cam 160 4causes the plunger 156 to be shifted toward the right for unseating theball 138.

The cam is also adapted to actuate a switch 166 through a cam followerball 168 which engages a plunger 170 of the switch. The switch ismounted conveniently at the side of the body member 14 by a bracket 172.An electrical conductor 174 connects the switch 166 with a relay 176(FIGS. 1 and 2) of known construction, which is electrically connectedfor controlling starting and stopping of the motor 12. Thus, the cam 160which is adapted to be manually operated through the agency of the lever164 serves not only to control the functioning of the valve of the pumpunit, but also to control starting and stopping of the electric motor intimed relation with such functioning.

The unit thus far described is adapted to be operated in the followingmanner. In order to start the motor, the lever 164 is moved downwardlyor in a counterclockwise direction as viewed in FIG. 3. This movementactuates the switch 166 for energizing the solenoid relay 176. Thismovement does not, however, cause actuation of the plunger 156. Thus themotor is energized to drive the pump so that fluid under pressure isdelivered through the passageways and the check valve 126 to thecylinder 98 for raising the load 102. Then upon raising the lever to theposition shown in FIG. 3, the motor is stopped and the check valves 126and 138 function to prevent return flow of the fluid from the cylinder98 and the load of the work member 102 is retained in the elevatedposition. When it is desired to lower the load 102, the lever 164 isrotated from the position shown in FIG. 3 in a clockwise direction tothe dotted line position, thereby shifting the plunger 156 toward theright and unseating the check or release valve 138 for permitting thefluid to return from the actuator cylinder 98 to the reservoir.

As previously indicated, hydraulic liquid may be returned to thereservoir either through the conduit or pipe 82 or the conduit 110. Asshown in FIGS. 1, 2 and 5, these conduits extend from the member 14generally longitudinally toward a mid portion of the reservoir 22. Theseconduits respectively terminate in end portions 178 and 180 whichextends transversely of the reservoir and have discharge ends, FIG. 5,182 and 184 closely spaced with respect to and directed generallyperpendicular to adjacent portions of the reservoir side wall.

Baifles 186 and 188 are welded or otherwise secured to the inner wall ofthe reservoir and extend longitudinally substantially the full lengththereof. These baflles project a substantial distance into the reservoirfrom the wall in a manner such that they combine with the armate wall ofthe reservoir to define corners 190 and 192 in which the aforementioneddischarge ends 182 and 184 respectively of the return conduits arelocated. The arrangement is such that oil returning through the conduitsto the reservoir is directed against the wall in the so-called cornerportions 190 and 192 in the reservoir. This oil fans out along or isgently deflected by the wall of the reservoir with a minimum ofturbulence whereby to counteract tendency of aeration or foaming of theoil.

It will be apparent from the foregoing description that the presentinvention contemplates the provision of a very compact and eflicientlyoperable hydraulic unit which has very practical application ininstances where workpieces or loads are to be raised and lowered. Thusthe unit herein described is particularly suitable for use withequipment such as lift trucks and the like. Because of the simplicity inconstruction, the unit may be produced at minimum cost without sacrificeof sturdiness and ruggedness. Lift trucks and the like are sometimessubjected to rough treatment and severe usage. The design andarrangement of the unit as herein contemplated will meet all of thedemands of such usage with minimum repair or replacement.

While a preferred embodiment of the present invention has been shown anddescribed herein, it is obvious that many structural details may bechanged without departing from the spirit and scope of the appendedclaims.

The invention is claimed as follows:

1. A unit of the type described comprising a motor and a pump includinga common member therebetween, said motor and pump comprising drive shaftmeans extending through said common member, a fluid reservoir connectedto said common member and enclosing the pump, said pump including pumpchamber means having an inlet communicatnig with said reservoir and anoutlet, fluid passageway means in said common member communicating withsaid outlet and having a first port connectable with a device to beoperated by fluid under pressure and a fluid return port communicatingwith said reservoir, said passageway means including a bore extendingbetween opposite sides of said common member, first removable valve seatmeans in one end portion of said bore between said outlet and said firstport, second removable valve seat means in an opposite end portion ofsaid bore facing said first valve seat and located between said firstport and said return port, first and second valve elements respectivelyengaging said first and second valve seats, actuator means extendingthrough said second valve seat and shi-ftable for unseating said secondvalve element and allowing fluid to return to the reservoir, and meansmounted on said common member selectively for controlling starting andstopping of said motor and for shifting the actuator means to unseatsaid second valve element.

2. A unit, as defined in claim 1, which includes spring means compressedbetween said first and second valve elements for yieldably maintainingthe valve elements against their respective seats.

3. A unit, as defined in claim 1, wherein said first and second valveseats are disposed adjacent to and at opposite sides of said first port,said unit including guide means traversing said first port and engagingsaid valve elements for preventing the valve elements from entering saidfirst port.

4. A unit, as defined in claim 1, which includes a fluid return conduitconnected with said return port and extending into said reservoir, saidreservoir having a cylindrical side wall, a baflie secured to said sidewall and defining therewith a corner within said reservoir, said returnconduit having a discharge end disposed within said corner and directedtoward said cylindrical side wall.

5. A unit, as defined in claim 1, which includes pressure relief valvemeans in said common member between said inlet and said first valveseat, said relief valve means including a second fluid return portcommunicating with said reservoir.

6. A unit, as defined in claim 5, wherein said reservoir comprises acylindrical side wall and first and second bafiles secured to said sideWall and defining therewith first and second corner portions within thereservoir, first and second fluid return conduits respectivelycommunicating with said first and second mentioned fluid return portsand extending into said reservoir, said conduits respectively havingdischarge ends located with said first and second corner portions anddirected toward the cylindrical wall of the reservoir.

7. In a unit of the type described, a common member for providing oneend of a motor and also one end of a pump, said common member includingfluid passageway means therein comprising a bore extending therethrough,said member having a port intersecting a midportion of said bore, afluid inlet communicating with a first end portion of the bore and afluid return port communicating with a second end portion of the bore, afirst valve seat element removably disposed in said first end portion ofthe bore at one side of said first port, a second valve seat ele mentdisposed in said second end portion of said bore at an opposite side ofsaid first port, said second valve seat element being located betweensaid first port and said return port and arranged in axial alignmentwith and opposing relation to said first valve seat element, first andsecond valve elements respectively engaging said first and second valveseat elements, an actuator means extending through said second valveseat element and operable for unseating the second valve element fromits associated seat.

8. A unit, as defined in claim 7,. wherein said first and second valveseat elements respectively include threaded plug portions disposedwithin and. closing opposite ends of said bore.

9. A unit, as defined in claim 84, which includes relief valve meansdisposed in said common member and communicating with said passagewaymeans.

10. In a unit of the type described, pump means including a member, afluid reservoir connected With said member and including a cylindricalside wall, a bafile secured to and extending longitudinally of saidcylindrical side wall and defining therewith a comer portion within thereservoir, said pump means including a fluid return conduit extendinginto said reservoir, and said conduit including a discharge end disposedin said corner portion and directed toward said cylindrical wall.

References Cited UNITED STATES PATENTS 2,286,880 6/1942 Traut 137-565 X2,543,624 2/1951 Gabriel 52 X 2,767,736 10/ 1956 Lackinger 137-574FOREIGN PATENTS 825,010l 2/1938 France.

M. CARY NELSON, Primary Examiner R. B. ROTHMAN, Assistant Examiner US.Cl. X.R. 60-52; 137-574

